Field of the Invention
The present invention relates to an injection molding system, and more particularly, to an injection molding system for multi-color molding or multi-component molding, comprising an injection molding machine provided with an additional injection device.
Description of the Related Art
There is an increasing demand for injection molding machines capable of molding integral molded articles using a plurality of colors or materials. In order to mold these molded articles, a single injection molding machine is mounted with a plurality of injection devices, which serve for successive injection. In this way, molded articles can be molded from materials of a plurality of colors or types. This molding method is called multi-component or multi-color molding, on account of the use of different resin materials or the same resin material of different colors in a plurality of injection devices. In the description herein, these molding methods will be generally called the multi-component molding methods, and the injection molding machine with a plurality of injection devices for the multi-component molding will be referred to as the multi-component molding machine.
The multi-component molding machine used may be a dedicated machine comprising a plurality of injection devices previously arranged around a single mold clamping device or a general-purpose machine in which an general-purpose injection molding machine comprising a single mold clamping device and a single injection device is provided with additional injection devices extending at right angles to the injection direction of the injection molding machine.
Techniques particularly related to multi-color, multi-component molding machines of the dedicated machine type are disclosed in Japanese Patent Applications Laid-Open No. 2001-79877 and No. 2001-121572.
In an injection molding machine, moreover, a device is provided with some movable doors. These movable doors are configured to be closed during the operation of the injection molding machine and opened when a molded article is to be removed from a mold or a discharged resin is to be removed and discarded. Thus, the movable doors are necessary for molding work. When the movable doors are open, however, movable parts of the injection molding machine are accessible, so that power in the injection molding machine is interrupted for the safety of operators.
Japanese Patent Applications Laid-Open No. 2000-37758, No. 4-278322, No. 2007-230113, No. 2002-187184, and No. 2011-240689 disclose techniques in which power in injection molding machines is thus interrupted for the safety of operators when movable doors of the injection molding machines are opened.
Although the techniques related to the multi-color, multi-component molding machines of the dedicated machine type are disclosed in Japanese Patent Applications Laid-Open No. 2001-79877 and No. 2001-121572, particulars related to the open/close operation of movable doors of the molding machines are not.
Although the open/close operation of the movable doors of the injection molding machines and interruption of the operation of the molding machines are disclosed in Japanese Patent Applications Laid-Open No. 2000-37758, No. 4-278322, No. 2007-230113, No. 2002-187184, and No. 2011-240689, cooperation between movable doors of respective injection devices of the multi-color, multi-component molding machines and the like are not.
According to the multi-component molding machine in which the injection molding machine and the additional injection devices additionally attached thereto are connected to one another, operators' safety sometimes cannot be secured by only interrupting power in the device of which a movable door is opened.
This case will be described with reference to FIG. 2. FIG. 2 is a top view of an injection molding machine 1 for multi-color, multi-component molding. Numeral 10 denotes an injection mechanism section, numeral 14 denotes a mold clamping mechanism section, numeral 16a denotes a fixed mold and numeral 16b denotes a movable mold, respectively. The injection mechanism section 10 injects a resin (not shown) into the fixed mold 16a. The mold clamping mechanism section 14 serves to move the movable mold 16b forward and backward so that mold clamping is achieved by the fixed mold 16a and the movable mold 16b. The fixed mold 16a and the movable mold 16b define a mold operation area 18. Further, numerals 12a and 12b individually denote movable doors attached to the injection molding machine 1.
The injection molding machine 1 is additionally provided with an additional injection device 2 for multi-component molding. Numeral 20 denotes an injection mechanism section of the additional injection device 2, and numeral 28 denotes an area for resin discharge from the injection mechanism section 20. Further, numerals 22a and 22b individually denote movable doors attached to the additional injection device 2.
In the multi-component molding machine thus constructed so that the injection molding machine 1 and the additional injection device 2 are connected to each other, an operator's hand or the like is allowed to access the other injection device when the movable doors are opened. If the movable doors 22 (22a and 22b) on the side of the additional injection device 2 are opened, for example, the operator can access the mold operation area 18 on the side of the injection molding machine 1, as well as the resin discharge area 28 on the side of the additional injection device 2. If the hot resin is discharged from the additional injection device 2 when the movable doors 22 on the side of the additional injection device 2 are open, therefore, it is necessary to interrupt power in the injection mechanism section 10 and the mold clamping mechanism section 14 of the injection molding machine 1, as well as power in the additional injection device 2, as a safety measure to prevent the operator from getting burned.
To perform this safety measure, the open/close states of the movable doors are reciprocally input and output between the injection molding machine 1 and the additional injection device 2. When the movable doors 12 on the side of the injection molding machine 1 are opened, the power on the side of the additional injection device 2, as well as the power on the side of the injection molding machine 1, is interrupted. When the movable doors 22 on the side of the additional injection device 2 are opened, in contrast, it is necessary only that the power on the side of the injection molding machine 1, as well as the power on the side of the additional injection device 2, be interrupted.
The injection molding machine 1 comprises the plurality of movable doors 12 (12a and 12b), which are each provided with a plurality of switches (not shown) for confirmation of opened and closed positions. If state signals from all the position confirmation switches on the movable doors and those from position confirmation switches on other movable doors are reciprocally input and output between the injection molding machine 1 and the additional injection device 2, therefore, the number of signals increases, possibly wire arrangement is complicated.
Thus, in order to prevent the increase of the number of signals between the injection molding machine 1 and the additional injection device 2, the machine 1 and the device 2 are individually provided with controllers, which can determine whether or not either of the movable doors 12 of the injection molding machine 1 is opened. If the result of the determination is output to the controller of the additional injection device 2, the wire arrangement can be simplified. The wire arrangement can also be simplified if the result of determination of whether or not either of the movable doors 22 of the additional injection device 2 is opened, in contrast, is output to the controller of the injection molding machine 1.
With this configuration, the wire arrangement between the injection molding machine 1 and the additional injection device 2 can be simplified. In each of the controllers of the machine 1 and the device 2, however, a signal indicative of the result of determination of whether or not either of the movable doors is opened is output to the destination controller. Accordingly, the destination controller having received the signal cannot identify the movable doors of which the position confirmation switches are operated. If any of the position confirmation switches is out of order, therefore, detection of the disabled switch takes time, possibly decreasing maintainability.